The Core has two objectives. First, its mission is to provide state-of-the-art light microscopy instrumentation for the Lab of Receptor Biology and Gene Expression. Second, the Core provides support to anyone in the CCR who requires assistance with fluorescence imaging. Present work in the Core revolves around four different general techniques: structural studies such as colocalization of different fluorescent markers, time-lapse analysis to follow how cellular components change over time, fluorescence recovery after photobleaching to measure mobility and binding of cell molecules and fluorescence resonance energy transfer to measure molecular interactions in live or fixed specimens. The following techniques are currently being adapted for the needs of the Core users: Number and Brightness quantification of the diffusion and binding rates of cell molecules and Super resolution imaging (PALM/SIM/dSTORM). The Core is building a Single Molecule /PALM /dSTORM microscope for the further development of single molecule tracking and molecule counting by superresolution.